The long range goal of this research program is to continue to use modern neuroanatomical tracing methods to analyze, in significant detail, the organization of extrageniculate visual pathways in mammals. Cats, Galagos and tree shrews will be the primary experimental animals, however, other mammals may be used for comparative studies. Specifically, the major thrust of my research endeavors for the next three years will focus upon defining the basic connections of the pretectal complex. These studies will be carried out both at the light and electron microscopic levels. Tracing methods include; 1) the anterograde transport of 3H-amino-acids, 2) the anterograde and retrograde transport of horseradish peroxidase, and 3) the retrograde transport of fluorescent dyes. I also plan to continue to study the connections of visual centers which are closely related to the prerectal complex. Such areas include the retina, the mesencephalic reticular formation, regions of the neocortex, the lateral nucleus of the thalamus and certain cranial nerve nuclei which receive an input from the pretectum.